"I was pretty much asymptomatic, felt for the most (part) pretty normal for two weeks (of isolating)," Matthews said, according to TSN's Kristen Shilton. "I did my quarantine and I'm healthy now, so it's all good."
The 22-year-old was deemed fit to play Sunday and joined the Maple Leafs for the opening of training camp Monday.
Matthews said his positive test didn't impact his ability to prepare for the 24-team postseason, though he wasn't able to skate while in quarantine.
"(It) didn't really hinder my training, I was able to do stuff at home," he said. "Obviously wasn't able to leave or anything. I think that's really the only thing that kind of took a hit for me. I was skating beforehand and having to take two-and-a-half, three weeks off obviously kind of catches up to you."
The 6-foot-3 pivot potted a career-high 47 goals and 80 points through 70 games this season, finishing third in the league in the former category.
The NHL confirmed Monday that a total of 43 players have tested positive for COVID-19 since Phase 2 of the league's return-to-play plan commenced on June 8.